Advantages of DPSK modulation | disadvantages of DPSK modulation
This page covers advantages and disadvantages of DPSK modulation over BPSK and its basics. It mentions benefits or advantages of DPSK modulation and drawbacks or disadvantages of DPSK modulation.
What is DPSK modulation?
As we know, BPSK is simpler and more power efficient modulation technique; But it has a low bandwidth efficiency. Hence BPSK is used for low speed communications.
DPSK stands for Differential Phase Shift Keying. It is the version of BPSK. In DPSK, there is no absolute carrier phase reference, instead transmitted signal itself used as phase reference. There are various applications of DPSK such as WLANs, Bluetooth and RFID communication. The most popular among them is its use of Bluetooth where π/4 - DQPSK and 8-DPSK modulation variants of DPSK has been employed.
Figure depicts the process of DPSK modulation using DPSK modulator in the form of a block diagram. In DPSK modulation, serial binary data pass through X-NOR gate and the output is fed back via 1 bit delay. The resulting bit stream is applied to the balanced modulator to produce DPSK signal.
Figure depicts the process of DPSK demodulation using DPSK demodulator in the form of a block diagram. In DPSK demodulation, DPSK signal is passed to the balanced modulator and 1 bit delay circuit. The resulting signal is passed to the LPF which produces binary data. This is passed to comparator circuit (or schmitt trigger circuit) to produce clean and high speed binary levels.
Benefits or advantages of DPSK modulation
Following are the benefits or advantages of DPSK modulation:
➨DPSK modulation does not require carrier at its receiver circuit. Hence complex circuits are not needed.
➨Bandwidth requirement of DPSK is less compared to BPSK modulation.
Drawbacks or disadvantages of DPSK modulation
Following are the drawbacks or disadvantages of DPSK modulation:
➨Probability of error or BER (Bit Error Rate) is higher in DPSK compare to BPSK.
➨Noise interference in DPSK is more.
➨DPSK modulation uses two successive bits for its reception. Hence error in first bit creates error in second bit and consecutively error propagates.
Conclusion: In order to understand the advantages of DPSK and disadvantages of DPSK one has to understand DPSK modulation basics.